In medical settings, an affected part in internal organs, skeletons, and the like is photographed, for example, with X-rays for various tests and diagnoses. Through application of recent digital technology, a dynamic image (an image group including a plurality of frame images) in which movement of an affected part is captured, for example, with X-rays can be acquired relatively easily.
In the recent digital technology, a dynamic image of a subject region including a diagnosis target region can be photographed with use of a semiconductor image sensor such as a flat panel detector (FPD), and thus an attempt to perform pathological analysis and diagnosis based on motion analysis of the diagnosis target region and the like, which cannot be performed in still image photography and diagnosis by conventional X-ray photography, is made. Particularly in dynamic analysis of the chest using X-rays, the following study is conducted; ventilatory information and blood flow information in the lung field are extracted, and dynamic functions related to a density change in the lung field and movement of blood flow at every position are quantitatively analyzed to support diagnosis and/or treatment (CAD for X-ray moving images).
As a method for achieving quantitative analysis described above, technology for analyzing a temporal change based on frame images constituting a dynamic image of the chest to generate analysis information effective in diagnosis has been proposed.
For example, Patent Document 1 discloses technology for separately using filters in such a manner that a high-pass filter is used to perform blood flow analysis and a low-pass filter is used to perform ventilatory analysis to eliminate the effects of density values of blood flow and ventilation on each other to thereby accurately extract ventilation and blood flow using inter-filter differences.
Patent Document 2 discloses technology for sorting frame images depending on whether each of the frame images belongs to an arterial phase or a venous phase to generate integrated images.
Patent Document 3 discloses technology for measuring the positions of left and right portions of the diaphragm and the apical portions of the lungs, acquiring moving amounts, and displaying a graph showing movement based on the moving amounts.
Patent Document 4 discloses technology for calculating a feature amount (period length and/or amplitude) for each period, and displaying a graph showing the feature amount as diagnosis support information.
Furthermore, Patent Document 5 discloses technology for selecting a plurality of important images to display a list thereof as thumbnails, and playing back a moving image through operation to select a thumbnail.